Question about Ford Expedition

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I have a 2010 Ford Expedition and there is a knocking sound when the A/C is on, any answers?

The knock under the dash board from the center to the passenger side. it appears to be only when the A/C is on or the fan. It will knock for about 5 seconds then will get quiet and then knock again a few minutes later.. Since this began it is also knocking as soon as we turn the vehicle on.

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  • Chris Oct 27, 2012

    the noise is like someone is physically tapping on the dash.



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  • 13 Answers

It tercould be a blend door motor,Try get in turn off everying.Then start it and if you here anything,if not turn on the heater and turn the hot and cold switch. see if it stops.a nother thing open the hood start it up check the passenger front end see if you hear it up there. if so i think the air compressor for air ride is there.

Posted on Oct 28, 2012


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Posted on Jan 02, 2017

  • 166 Answers

SOURCE: I have a 2009 Dodge

sounds like u have an electric mode door motor,in ur hvac housing stripped . move the mode selector to different positions to amplify noise an sort of control noise. u have a blend air door motor, mode position motor, for example inside air an outside air recirculating door motor, or defroster mode motor or actuate the heater position an u should b able to control noise by changing modes, thats wen u know u found it wen u can make the noise come an go. also one of ur selector positions is obviously not workin due to a stripped motor or broken blend door. good luck

Posted on Apr 09, 2011

  • 20 Answers

SOURCE: Knocking Noise from Dash Board

What sort of noise? Could it be the winscreen wiper motor?

Posted on Oct 10, 2008

  • 659 Answers

SOURCE: knocking sound L-Rear side

it is the blend door actuator for the rear heat-a/c they good bad and make a thump or clicking sound

Posted on May 20, 2009

  • 16 Answers

SOURCE: Knocking noise Renault Megane 1998

this is a white box on the other side of the passangers dash board. lift up the bonnet and disconnect it. that will stop the noise but now your heaters will only get warm instead of hot. its some sort of flap to do with the heater matrix. realy anoying

Posted on Mar 04, 2010

  • 64 Answers

SOURCE: Knocking noise on passenger side under dash.

sounds like you have a loose fan cage for the ac/heater.

Posted on Nov 13, 2010

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